Uterine fibroids are common, non-cancerous growths that develop within the muscular wall of the uterus. Also known as leiomyomas or myomas, they affect a significant portion of women during their reproductive years, with prevalence estimates reaching up to 80% by age 50. While many women experience no noticeable symptoms, these growths can cause considerable discomfort and are a known source of pelvic pain and pressure.
Understanding Uterine Fibroids
Uterine fibroids are tumors composed of smooth muscle cells and fibrous tissue that originate in the uterine wall. These growths vary drastically in size, from microscopic to large masses that can fill the pelvic area. Fibroids are classified based on their location within the uterus, which influences the symptoms experienced.
Intramural fibroids are the most common, developing within the muscular layer (myometrium). Subserosal fibroids grow on the outer surface of the uterus, sometimes extending into the pelvic cavity. Submucosal fibroids are the least common but often cause the most severe symptoms because they develop just beneath the uterine lining and protrude into the uterine cavity.
How Fibroids Generate Pelvic Discomfort
Fibroids cause pelvic pain through several mechanisms related to their size and location. Large fibroids, particularly intramural and subserosal types, exert continuous pressure on adjacent pelvic organs. This mechanical pressure on the bladder can lead to frequent urination, while pressure on the rectum can cause constipation or a feeling of fullness. This often results in a chronic, dull ache or a persistent sensation of heaviness in the lower abdomen.
A second mechanism involves fibroid degeneration, which causes a sudden onset of severe, acute pain. This occurs when a fibroid grows so rapidly that its blood supply is outpaced, causing the tissue to lose oxygen and die. The degeneration process releases chemical substances that trigger sharp, stabbing pain, which can last from a few days up to a few weeks.
Submucosal fibroids, even when small, contribute to significant pelvic pain in the form of severe menstrual cramping. These growths distort the uterine cavity, forcing the uterus to contract more forcefully in an attempt to expel them. In rare instances, a pedunculated fibroid attached by a stalk can twist, cutting off its blood supply and causing sudden, intense pain that requires immediate medical attention.
Related Symptoms Beyond Pelvic Pain
Fibroids can manifest a range of other symptoms based on their physical impact. The most common complaint is heavy or prolonged menstrual bleeding (menorrhagia), which can lead to passing large blood clots. Excessive blood loss can result in iron-deficiency anemia, causing fatigue and weakness.
Fibroids located on the posterior wall may press against nerves in the lower back, causing back pain or, rarely, pain that radiates down the leg (sciatica). Pressure on the urinary tract can cause difficulty emptying the bladder or, in rare cases, urinary retention. Some women also experience pain during sexual intercourse (dyspareunia), particularly if the fibroids are located near the cervix.
Diagnosing Fibroids
Diagnosis typically begins with a thorough medical history and a pelvic examination. During the exam, a healthcare provider may feel an enlarged or irregularly shaped uterus, suggesting the presence of fibroids. The preferred initial imaging technique is pelvic ultrasound, which uses sound waves to create a picture of the uterus and ovaries.
An ultrasound determines the size, number, and exact location of the fibroids, often performed both abdominally and transvaginally for better detail. In more complex cases or when surgical planning is required, a Magnetic Resonance Imaging (MRI) scan may be used. MRI provides detailed mapping of the fibroids and surrounding structures, useful for distinguishing them from other pelvic masses or conditions like adenomyosis.
Managing and Treating Fibroid Symptoms
Treatment for symptomatic fibroids depends on the severity of symptoms, the size and location of the growths, and the patient’s desire to preserve fertility. For mild symptoms, over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) can manage pain. Hormonal therapies, such as birth control pills or progestin-releasing intrauterine devices, help control heavy bleeding. Gonadotropin-releasing hormone (GnRH) agonists can temporarily shrink fibroids by blocking estrogen and progesterone production, often used before surgery.
Minimally invasive procedures are options for those who require more than medication but wish to avoid major surgery. Uterine Fibroid Embolization (UFE) involves injecting small particles into the arteries supplying the fibroids, cutting off blood flow and causing them to shrink. For fibroids that protrude into the uterine cavity, a hysteroscopic myomectomy can remove the growth using instruments passed through the vagina and cervix.
Surgical options provide the most definitive treatment for severe or persistent symptoms. A myomectomy removes only the fibroids, preserving the uterus, and is often the choice for women who wish to become pregnant. Hysterectomy, the removal of the entire uterus, permanently resolves fibroid symptoms and is reserved for women who no longer desire future childbearing.